SHORT COMMUNICATIONS

ORNITOLOGIA NEOTROPICAL 18: 301–303, 2007 © The Neotropical Ornithological Society

OBSERVATIONS ON THE NESTING OF SPOT-BACKED ANTBIRD (HYLOPHYLAX NAEVIA) IN EASTERN

Harold F. Greeney

Yanayacu Biological Station & Center for Creative Studies c/o Foch 721 y Amazonas, Quito, Ecuador. E-mail: [email protected]

Observaciones sobre el nido del Hormiguero dorsipunteado (Hylophylax naevia) en el este del Ecuador. Key words: Hylophylax naevia, Spot-backed Antbird, feeding rate, nest, hatching, nestling, egg, parental care.

Hylophylax antbirds are a small genus of Ecuador, as well observations from five addi- plump, short-tailed antbirds ranging from tional nests. to northern , generally On 26 August 2003, I encountered three below 1100 m elevation, and often associated nests, each with incubation underway, at the with ant swarms (Hilty & Brown 1989, Tiputini Biodiversity Station (0º45’S, 75º45’W, Ridgely & Tudor 1994, del Hoyo et al. 2003). elev. 250 m), located in the Sucumbios Prov- The Spot-backed Antbird (H. naevia) ranges ince, on the south side of the Napo River, in from southeastern , southern Vene- eastern Ecuador (see Freiberg & Freiberg zuela and the Guianas to eastern Ecuador and 2000 for a complete site description). I found , and northern Bolivia and Amazonian three additional nests in the private reserve of (Ridgely & Tudor 1994). Hylophylax n. the Mushullacta community (00º22’S, 78º teresae occurs from eastern Ecuador, south of 08’W, elev. 1150 m) near the Napo-Galeras the Rio Napo, to northeastern Peru and east portion of Sumaco National Park. I found all to southwestern and southcentral Brazil, of these nests from 3–11 April 2005, and all generally in terra firme below 700 m, but were well within primary forest. Of these, two occasionally as high as 1250 m (Ridgely & were incubating and one contained a very Greenfield 2001, del Hoyo et al. 2003). What young nestling. is known of its nesting has recently been sum- All nests were thick, messy, fungal rhizo- marized in del Hoyo et al. (2003), mostly from morph and rootlet cups (with much dead leaf unpublished observations. Ecuadorian data debris attached ) slung between two horizon- include active nests from late April to May tal branches arising from the main trunk of and September, but other observations small saplings. In all cases the two sides of the support breeding throughout the year in nest were attached to branches leaving the this area. Here I provide observations on trunk at a roughly 90º angle to each other and parental care at a single-nestling nest from at different levels, one above the other (mean

301 GREENEY distance between the two 8.5 cm, range 4–15 On 27 August at Tiputini, the egg in one cm). In the single exception the lower portion nest hatched and behavior at this nest was of the nest was attached directly to the stem at videotaped from 05:30 h to 18:30 h on 27 and a vertical Y branching. Mean nest height was 28 August. A video camera was placed on a 88 cm (range = 40–1.1) and mean supporting tripod, slightly above the level of the nest, sapling height was 120 cm (range = 1–1.5). approximately 5 m from the nest. Adult Mean nest measurments (cm ± SD) for 4 behavior appeared unaffected by the camera nests were: outside height 6.8 ± 1.0, outside and, while aware of my presence, adults did width 7.0 ± 0.8, inside width 4.8 ± 0.2, inside not flush from the nest during my activity at depth 4.8 ± 0.2, tail of material below nest the camera. 24.0 ± 15.0, supporting branch diameter 0.5 Of the 60 prey items offered to the nest- ± 0.1, diameter of sapling at nest height 0.9 ± ling by the adults, only seven were estimated 0.3. Three nests were in unknown, but differ- to be larger than 5 mm in length. Because of ent, species of woody saplings, and others the small size of the prey items, none were were in Pourouma (Cecropiaceae), Piper (Piper- able to be identified, but appeared to be small aceae), and unknown Rubiaceae saplings, winged insects. On several occasions, espe- respectively. All three nests at Tiputini were cially on the day of hatching, the adults situated at or near the bottom of 3–5 m deep brought food that was not fed to the nest- depressions and 0.75–8 m from small lings. In each case, after up to 45 s perched on streams. The three nests at Mushullacta were the rim with prey, occasionally nudging the also in small depressions, none of which con- nestling, the adult ate the prey item. On most tained running water. They were, however, occasions, when adults were switching places 10–40 m from small streams. One nest was at the nest, a soft squeaking sound was pro- built immediately adjacent to, and slightly duced by one or both of the adults, and below, what appeared to be an old nest of this appeared to signal the approach of one and species, and incorporated some material from the awareness of the other. this structure. At the Tiputini, two of the On 27 August, while setting up the cam- nests, while separated by a 4–5 m high ridge era, the female was seen sleeping on the nest, of land, were found along the same winding which she left before 06:05 h. No adult visited stream and situated no more than 40 m apart the nest until 06:40 h, when the female in a straight line. arrived and removed the egg shell. This was Five nests contained a single, buffy white the first indication that the egg had hatched egg, heavily streaked and spotted with dark and from this time until 18:00 h, adults red-brown such that most of the ground brooded the nestling for 78% of the day. On- color was obscured. Mean egg measurements bouts averaged (± SD) 18.8 ± 16.1 min and were (±SD) 19.9 ± 1.2 by 14.5 ± 0.4 mm off-bouts averaged 5.2 ± 5.5 min. The longest (range = 19.0–21.8 by 14.1–15.0 mm). Both period the nestling remained uncovered was sexes were incubating at all of these nests. 20.1 min. On 28 August the female left the The newly hatched nestling at Tiputini nest for the first time just after 06:00 h. Until and the young nestling found at Mushullacta 18:00 h the adults again brooded the nestling were nearly identical in appearance. Their skin for 78% of the day. On bouts averaged 21.2 ± was black, including the legs, feet, and cloaca. 16.6 min and off-bouts averaged 5.9 ± 7.7 Their gapes were pale yellow-white with black min. The nestling was never left uncovered mandibular tips and the mouth linings were for longer than 36.9 min. The male per- bright yellow. formed 69% of the brooding on 27 August

302 SHORT COMMUNICATIONS and 56% on 28 August. potentially breeding year-round. On 27 August the female made 14 trips to the nest while the male made 24 trips. The ACKNOWLEDGMENTS female arrived without food on half of these trips and was unsuccessful at feeding the nest- Thanks to the staff at the Tiputini Biodiver- ling on an additional three trips. The male sity Station and Juan Miguel and Lori arrived only twice without food and unsuc- Espinoza of the Andean Studies Center for cessfully offered food on seven trips. Thus, their logistical support. I thank Rudy Gelis for throughout the day the nestling was fed a total comments on earlier versions of this manu- of 15 times by the male and only four times by script. Thanks to the PBNHS for all the inspi- the female. The male retrieved and ate two ration and to Ruth Ann and John V. Moore fecal sacs and the female ate one. On 28 for financial assistance. This study was further August the female made 12 trips to the nest, funded in part by a Pamela & Alexander F. arriving without food only twice. She success- Skutch Award, the Hertzberg Family Founda- fully fed the nestling nine times. The male tion, and Timothy Metz. This is publication made 22 trips and arrived only once without number 106 of the Yanayacu Natural History prey. He was successful in all of his attempts Research Group. to feed the nestling. The nestling was fed 30 times during the day and produced six fecal REFERENCES sacs, three of which were eaten by the male del Hoyo, J. A., A. Elliot, & J. Sargatal. 2003. Hand- and three by the female. book of the of the world. Volume 8: While brooding, the female, but never the Broadbills to tapaculos. Lynx Edicions, Barce- male, was observed to occasionally stand and lona, Spain. peer into the nest. After standing, she fre- Dobbs, R. C., P. R. Martin, C. Batista, H. Montag, quently leaned into the nest and rapidly thrust & H. F. Greeney. 2003. Notes on egg laying, her bill in and out of the lining of the nest. incubation and nestling care in Scaled This behavior has been observed in a variety guatimalensis. Cotinga 19: 65–70. of species including Bicolored Antvireos Freiberg, M., & E. Freiberg. 2000. Epiphyte diver- sity and biomass in the canopy of lowland and (Dysithamnus occidentalis) (Greeney 2004), and motane in Ecuador. J. Trop. Ecol. 16: Scaled Antpitta (Grallaria guatemalensis) (Dobbs 673–688. et al. 2003). Various functions of this behavior, Greeney, H. F. 2004. Breeding behavior of the including parasite removal and egg rolling, Bicolored Antvireo (Dysithamnus occidentalis). have been postulated (Halftorn 1994, Dobbs Ornitol. Neotrop. 15: 349–356. et al. 2003). Haftorn, S. 1994. The act of tremble-thrusting in tit While del Hoyo et al. (2003) give the clutch nests, performance and possible functions. size for the Spot-backed Antbird as 1–3, Fauna Norv. Ser. C, Cinclus 17: 55–74. “probably most often 2,” they also note that Hilty, S. L., & W. L. Brown. 1986. A guide to the one-egg nests were most frequently reported birds of Colombia. Princeton Univ. Press, Prin- from French Guiana but that a nest with three ceton, New Jersey. Ridgely, R. S., & G. Tudor. 1994. The birds of young was found in Ecuador. Until more South America. Volume II: The Suboscine Pas- information is published it is difficult to spec- serines. Univ. Texas Press, Austin, Texas. ulate on the normal clutch size in Ecuador. It Ridgely, R. S., & P. J. Greenfield. 2001. The birds of is is reasonable to believe, however, that there Ecuador. Cornell Univ. Press, Ithaca, New may be seasonal variation in clutch size, York. reflecting varying resources, in a species Accepted 23 October 2006.

303